1,4-Azaborine based unfused non-fullerene acceptors for organic solar cells

Abstract

1,4-Azaborine, containing both boron and nitrogen in an aromatic hydrocarbon, displays unique electronic properties compared with its all-carbon analogue and shows great potential as multiresonant thermally activated delayed fluorescence materials....

Organoboron-embedded functional materials: recent developments in photovoltaic and luminescence properties

“…Compared to BNBPembedded polymeric acceptor materials, the development of donor materials is lagging and has been rarely reported in recent years, but it does not mean that BNBP-based donor materials are not promising. [146][147][148][149][150][151][152][153] In 2021, Pang et al reported a new B-N building block and the embedded polymer 107 as an active layer donor material in OSC devices, which has complementary light absorption and matched energy levels to the acceptor Y6-BO. Thermal gravimetric analysis suggested that 107 is thermally stable with a decomposition temperature of approximately 400 1C.…”

B─N Covalent Bond‐Based Nonfullerene Electron Acceptors for Efficient Organic Solar Cells

“…[34][35][36][37] BN heterocycles, compared to carbonaceous counterparts, demonstrate unique electronic properties owing to their different 𝜋-electron distributions and dipole moments, making them highly promising for organic optoelectronic materials. [38][39][40][41] For example, 1,4-BN heterocycles have been widely used to construct multiresonant thermally activated delayed fluorescence materials. [42][43][44] Generally, boron and nitrogen atoms can form B ← N coordinate bonds and B─N covalent bonds, respectively.…”

Single and Double Alkoxybenzothiadiazole–Dithienosilole-Based Nonfused Ring Electron Acceptors for Organic Solar Cells

“…However, FREAs have disadvantages that have limited their commercial applications, including high synthetic complexity, high production costs, and low molecular design flexibility. − To overcome these problems, nonfused electron ring acceptors (NFREAs) have been proposed. NFREAs consist of central core units connected with aryl–aryl C–C single bonds. − NFREAs exhibit high flexibility with regard to chemical modification through simple synthetic methods, allowing low-cost production and easy modification of their band gap energy ( E g ), highest occupied molecular orbital/lowest unoccupied molecular orbital (HOMO/LUMO) levels, and molecular orientations. − However, the additional degrees of freedom afforded by C–C bond rotation in NFREAs can lead to lower molecular planarity and increased conformational isomerism, thereby reducing effective charge transfer. To maintain the molecular planarity of NFREAs, conformational locking using different noncovalent interactions involving H···S, F···S, O···S, and N···S was introduced. − Among the types of NFREA backbone structures developed to date, the A–D–A′–D–A type is one of the most popular.…”